Three years of relative calm were shattered in Bangkok on Monday when antigovernment protesters occupied two government ministries and threatened several others, prompting embattled Prime Minister Yingluck Shinawatra to bring the city and nearby provinces under the powers of the Internal Security Act.

“Our national-security service is now monitoring the protest, and we are trying to handle the protesters without any violence,” Yingluck said on Monday. Police and protesters scuffled in the street, and a German journalist was reportedly attacked while taking photos near Bangkok’s Dusit district.

Not satisfied with occupying the ministries of Foreign Affairs and Finance — as well as the government’s public relations department — protest leader Suthep Thaugsuban, a former MP for the opposition Democrat Party, called upon the Thai people to “rise up and seize more government buildings” on Tuesday amid what he deemed a “people’s revolution.”

Heeding Suthep’s call, hundreds of protesters gathered in front of the Agriculture and Transport ministries at lunchtime on Tuesday, with civil servants told to go home. The Ministry of Tourism and Sports, as well as the Interior Ministry, are also apparently earmarked for occupation.

Demonstrators accuse the 46-year-old Yingluck, who was elected in July 2011 as head of the Pheu Thai party, of corruption for attempting to pass an amnesty bill that would have allowed her brother, former Prime Minister Thaksin Shinawatra, to return home from exile. Although ostensibly an attempt to reconcile fractious Thai society after years of color-coded political strife, at the last moment the legislation was extended to effectively pardon Thaksin of graft charges he was convicted of in absentia after his ousting in a military coup in 2006.

The bill was subject to an unprecedented bipartisan outcry and stalled at the Senate. Nevertheless, the attempt to pass it was seized upon by the opposition to sow discord. Suthep has vowed to resist any attempt to arrest him for intruding into government buildings and plans to remain with protesters in the Finance Ministry, where there was a conspicuous absence of police on Monday. Water and electricity supplies to all three occupied buildings have been cut.

According to Thitinan Pongsudhirak, professor of political science at Chulalongkorn University in Bangkok, “the government will be forced to act today, and the protesters will ramp up their rhetoric and activism in order to provoke an overreaction.”

Bangkok is sadly all too familiar with that scenario. Years of bloodletting between political rivals the Red Shirts (generally rural poor that support Thaksin) and Yellow Shirts (urban royalists and long-standing Thai elites who largely back the Democrat Party) culminated in street battles in April through May 2010 that left more than 80 dead and 2,000 injured. Suthep, spearheading the current unrest, oversaw the government crackdown three years ago while in power.

The Democrat Party’s game plan is apparently to paralyze the government so that an outside agency takes action. Previously the military and judiciary system moved to remove Thaksin-backed administrations that became embroiled in similar discord, although both are wary of getting their hands dirty again.

This time, says Thitinan, the “National Anti-Corruption Commission could step in as there are some outstanding charges that could dislodge the Yingluck government.” Such a move is “quite likely,” he adds, as the Establishment powers are fervently against Thaksin.

Yet there seems little way out of Thailand’s long-standing political quagmire. Despite the virulence of the Bangkok protests, Thaksin-backed parties have won the previous five elections with significant majorities. Ousting Yingluck would seem to achieve little other than usher in another Thaksin proxy while incurring massive reciprocal Red Shirt protests in the interim. (Suthep is all too aware of this and even apparently called for the installation of an absolute monarchy during a recent speech.)

Certainly, “the Red Shirts will be very angry, and they will do something very nasty in response,” says Thitinan. The last time a Thaksin-backed government was forced from power, in 2008, the country saw two years of mass protests and occupations, culminating in tanks rolling into central Bangkok’s shopping district and snipers, apparently ordered by the military, picking off protesters in the street.

So what hope is there of a peaceful resolution? It could rest with the emergence of a third and fourth party to water down the Southeast Asian kingdom’s vitriolic bipartisanship, says Thitinan. “A lot of Pheu Thai supporters disagree with Thaksin’s amnesty gambit, and a lot of Democrat Party supporters are angry with the current occupation of government ministries,” he explains, adding that “the situation is very fluid, volatile and unpredictable.”